The present invention generally relates to mapping or navigation. Traffic information may be displayed on a map. Road sensors or other sources of data (e.g., probe data) indicate traffic flow. To communicate the traffic flow, the roads on a map are color coded. For example, red indicates slow flow or congestion and green indicates high flow or an open road. However, color coding of the map has poor resolution. Greater resolution traffic flow may be difficult to distinguish using color modulation of the road.